ROI Calculator — Advertising Campaign ROI Online
ROI Calculator by Spilno Agency — a free online tool for calculating advertising campaign profitability. Enter your ad spend, revenue, number of purchases, and profit margin — and instantly get ROI, average order value, and customer acquisition cost.
What Is Advertising Campaign ROI
ROI (Return on Investment) measures how well your advertising pays off. It answers the key business question: how much profit does every euro invested in a campaign generate? If ROI is above 0%, your ads make money; if below — they burn it.
ROI = (Revenue × Profit margin − Ad spend) / Ad spend × 100%An important nuance: calculating ROI from full revenue is a common mistake. Revenue includes the cost of goods, so the formula uses margin profit (revenue multiplied by profit margin). That is why our calculator asks for your margin or markup.
What Metrics the Calculator Provides
| Metric | Formula | What it shows |
|---|---|---|
| ROI | (Revenue × Margin − Spend) / Spend × 100% | Return on your advertising investment |
| Average order value (AOV) | Revenue / Number of purchases | How much an average purchase brings |
| Cost per customer (CAC) | Spend / Number of purchases | How much acquiring one customer costs |
| ROAS | Revenue / Spend | Revenue generated per unit of ad spend |
| Profit from ads | Revenue × Margin − Spend | What remains after ads and cost of goods |
ROI vs ROMI vs ROAS: What Is the Difference
These three acronyms are often confused, although they answer different questions:
- ROAS (Return on Ad Spend) — how much revenue one unit of ad spend generated. It ignores the cost of goods: ROAS 3 at a 20% margin means you are losing money.
- ROMI (Return on Marketing Investment) — the return on marketing spend specifically. It accounts for margin but ignores other business costs.
- ROI — in a broad sense, the return on all investments. In an advertising context, ROI and ROMI are usually used interchangeably.
Our calculator computes ROI based on margin profit — the most practical approach for evaluating an ad campaign: it shows real money, not turnover.
Profit Margin or Markup: Which One to Enter
These are two ways of describing the same difference between price and cost — but the numbers differ, and confusing them distorts ROI:
- Profit margin — the share of profit in the selling price. Cost €100, price €150 → margin 33.3%.
- Markup — the percentage added on top of cost. Same numbers → markup 50%.
If you only know your markup — switch the calculator to “Markup” mode and it will convert automatically using the formula: Margin = Markup / (100 + Markup) × 100.
ROI Calculation Example
An online store spent €2,000 on Google Ads. The campaign generated 80 purchases with €12,000 in revenue. The product margin is 40%.
- Average order value: 12,000 / 80 = €150.
- Cost per customer (CAC): 2,000 / 80 = €25.
- ROAS: 12,000 / 2,000 = 6 — every euro spent brings €6 in revenue.
- Margin profit: 12,000 × 40% = €4,800.
- ROI: (4,800 − 2,000) / 2,000 × 100% = +140% — every euro invested comes back and brings another €1.40 in profit.
What Is a Good ROI
There is no universal benchmark — it all depends on margin, average order value, and repeat purchases. Rough guidelines:
- ROI < 0% — the campaign is losing money. Exception: deliberately breaking even or running at a loss for LTV — when customers return and buy again.
- ROI 0–50% — the campaign pays off, but the safety margin is thin. Optimise bids, audiences, and landing pages.
- ROI 50–200% — a healthy result for most e-commerce and service niches across Europe.
- ROI > 200% — a strong result. Often a signal that you can scale the budget without losing efficiency.
A quick break-even check: the minimum required ROAS = 100 / profit margin. At a 40% margin, ads pay off from ROAS 2.5; at a 20% margin — only from ROAS 5.
How to Improve Your Advertising ROI
- Cut underperforming campaigns and keywords. 20% of campaigns typically generate 80% of losses — find them in your reports and pause or rebuild them.
- Work on your average order value. Upsells, bundles, and free-shipping thresholds increase revenue without raising acquisition costs.
- Lower your cost per customer (CAC). Sharper audiences, negative keywords, better creatives, and fast landing pages reduce the cost per conversion.
- Set up accurate conversion tracking. Without reliable GA4 data, optimisation is impossible — algorithms learn from incomplete signals. Tag your campaigns with our UTM Builder.
- Consider LTV, not just the first purchase. If customers come back, your real ROI is higher than a single-transaction calculation shows.
If your advertising ROI is below expectations — request a free Google Ads audit or learn more about Google Ads management by Spilno Agency.
Frequently Asked Questions About ROI
How do I calculate the ROI of an advertising campaign?
ROI = (Revenue × Profit margin − Ad spend) / Ad spend × 100%. For example: spend €2,000, revenue €12,000, margin 40% → ROI = (4,800 − 2,000) / 2,000 × 100% = 140%.
What is the difference between ROI and ROAS?
ROAS shows the ratio of revenue to ad spend without accounting for the cost of goods. ROI factors in the profit margin and shows actual profit. ROAS 3 at a 20% margin means the campaign is losing money, even though revenue is three times higher than spend.
What if I don’t know my profit margin?
Leave the field empty — the calculator will compute ROI from full revenue and flag it in the results. For a realistic picture, though, margin is critical: check with your accountant or calculate it as (Price − Cost) / Price × 100%. If you only know your markup, switch the calculator to Markup mode.
What is considered a good advertising ROI?
Any ROI above 0% means the campaign pays off. For most e-commerce and service niches, a healthy range is 50–200%. ROI above 200% is a signal that the budget can be scaled.
Why is my ROI negative when ROAS is above 1?
Because ROAS ignores the cost of goods. Revenue can exceed ad spend, yet after subtracting the cost of goods no profit remains. The minimum break-even ROAS = 100 / profit margin: at a 25% margin, ads only pay off from ROAS 4.
Does the calculator store my data?
No. The calculator runs entirely in your browser — no numbers are sent to any server or stored anywhere.